The death of Hamas leader Yahya Sinwar has shaken up the war in the Middle East, with Israel now having eliminated the top leaders of the Palestinian militant group, including the officials who plotted the Oct. 7, 2023, attacks.   The Israeli military confirmed Thursday that Sinwar was killed in an operation in Gaza along with two other Hamas militants. It’s still unclear exactly how he died.  His death marks a new turn in the war in Gaza, which has raged for more than a year, with Israeli Prime Minister Benjamin Netanyahu now able to claim he has decimated the command structure of Hamas. Netanyahu, in a televised speech after Sinwar’s death, said Israel had “came to account” with Sinwar, the mastermind of the Oct. 7 attacks, which killed some 1,200 people in southern Israel and involved the kidnapping of 250 hostages. “Today evil has suffered a heavy blow, but the task before us is not yet complete,” he said. “Today we clarified again what happens to those who hurt us. Today we once again showed the world the victory of good over evil. But the war ... is not over yet.”  In the U.S., Pentagon press secretary Maj. Gen. Pat Ryder said Hamas has been “incredibly degraded” and added that Sinwar’s death presents an opportunity for the release of the remaining hostages.  Jonathan Spyer, director of research at the Middle East Forum, said the death of Sinwar is “extremely significant” for the Israeli military’s goal of destroying the organizational structure of Hamas.  But he cautioned it was unlikely to signal a new phase in the war, saying Hamas would reconstitute if Israeli troops were to withdraw from Gaza because Netanyahu has not formalized any plans for a postwar governing structure in the Strip.  “On a symbolic level, it's very important, but it does not in any way, I think, mean that Hamas as a movement will now begin to collapse,” he said. “It does not portend ... a situation in which Israel can simply now declare victory.”  Sinwar’s death was greeted with bipartisan enthusiasm in Washington — but opposing views on what should come next.  President Biden said in a statement that Sinwar’s death “proves once again that no terrorists anywhere in the world can escape justice, no matter how long it takes.”  “There is now the opportunity for a ‘day after’ in Gaza without Hamas in power, and for a political settlement that provides a better future for Israelis and Palestinians alike,” Biden said. “Yahya Sinwar was an insurmountable obstacle to achieving all of those goals. That obstacle no longer exists.”  Vice President Harris, the Democratic presidential nominee, said “it is time for the day after to begin.”  But Republicans expressed support for backing Netanyahu’s wider war aims in the region.  Speaker Mike Johnson (R-La.) said “justice has once again been served by the brave men and women of the Israeli military” but stressed that “the death of this man is not the end of Israel’s fight for survival.”  “At this moment, with the bloodthirsty leaders of Hamas and Hezbollah now gone, the Biden-Harris Administration must now work in tandem with Israel to apply a maximum pressure campaign against the head of the snake: Iran,” he said in a statement.  After a year of war, Hamas has been severely degraded, losing both its top commander, Mohammed Deif, and the former political leader, Ismail Haniyeh, in July.  Netanyahu also told the United Nations last month that Hamas has lost most of its battalions and military power.   Sinwar’s death is renewing the question of what Israel’s goal of destroying Hamas actually looks like.  Rose Kelanic, director of Middle East engagement at Defense Priorities, said killing the leaders of terrorist groups rarely terminates them as an organization and that Israel’s destructive campaign in Gaza, where more than 42,000 have died, is creating more instability.  “This is the moment that sort of shows how little victory there is to be had in Gaza,” she said. “This was a target that people had, and then they actually got the target.”  She said Netanyahu’s major shortcoming is that he has never “articulated a clear vision of what Gaza is going to be like when the war is done.”  That has the families of the Hamas hostages worried that their loved ones are now in more danger in the wake of Sinwar’s death, according to a statement from the Hostages and Missing Families Forum. “This is a critical, time-sensitive development as it relates to the hostages. Their lives are in great danger now more than ever,” said the parents of Israeli American hostage Omer Neutra, as relayed by the group.  And Einav Zangauker, whose son is among the hostages, said if Netanyahu does not take advantage of “momentum and does not place a new Israeli initiative on the table, even at the cost of ending the war, it means that he has decided to abandon my son Matan and the other hostages, with the aim of prolonging the war in order to fortify his rule.”  Sinwar was considered a major obstacle to any hostage and cease-fire release deal, as he had the ultimate authority to accept or reject conditions, even as he hid inside the vast tunnel networks Hamas built underneath Gaza.  Former State Department Middle East negotiator Aaron David Miller told CNN on Thursday that with Sinwar dead, there may be an opening in the talks because a peace deal is “the only way out of this if the organization is going to survive in some form.”  “But again, you have inertia and you have the need to continue to look for hostages rather than negotiate,” he said. “I don’t think the Israeli government position is going to immediately default into 'let's stop shooting and now let’s start talking.'”  State Department spokesperson Matthew Miller indicated Thursday that the U.S. hoped to use the moment to build diplomatic momentum.  He told reporters that Washington intends to redouble its efforts to get hostages home and “bring an end to this war” via “a new opportunity for negotiations.” Miller did not give specifics on what those efforts would be.  The broader Middle East conflict also risks expanding and escalating. Netanyahu is weighing a retaliatory strike against Iran, which fired some 180 ballistic missiles at Israel on Oct. 1, and Tehran is vowing revenge for any attack.  Israeli troops are also fighting against Lebanese and Iranian-backed militant group Hezbollah in a mission to create a buffer zone and return some 60,000 residents who have been displaced by Hezbollah firing rockets over the border since Oct. 8, 2023.  Jonathan Panikoff, director of the Atlantic Council’s Scowcroft Middle East Security Initiative, said Sinwar’s death provides the “best opportunity to convince their political leadership to make a deal for the hostages.”  But he stressed that the “interrelated challenges Israel is working through are unlikely to dissipate simply because Sinwar is no longer leading Hamas" and that Israel is likely to both retaliate against Iran and keep up operations against Hezbollah.  “Today marks an opportunity to begin to close one of the most painful chapters in Israel’s recent history, something that will only be completed once the hostages are released,” Panikoff said in a statement.  “But it is far from the end of the book. How Israel chooses to further leverage today’s success will determine whether the next chapters are better than this one.”